Distributed services for mesh networks

• US 7,808,987 B2
• Filed: 12/19/2006
• Issued: 10/05/2010
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Bauer, Fred, Du, Fan
• Primary Examiner(s): Phan, Man
• Assistant Examiner(s): Zhao, Wei
• Application Number:
  US11/612,777
• Publication Number:
  US 20070140239A1
• Time in Patent Office: 1,386 Days
• Field of Search: 370/389, 370/406, 709/217, 709/223
• US Class Current: 370/389
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4552 Lookup mechanisms between a plurality of directories; Synchronisation of directories, e.g. metadirectories
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/58 Caching of addresses or names
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

Nodes in a mesh network are configured to access centralized Internet Protocol (IP) services whenever the Internet infrastructure is accessible and then dynamically switch to providing the IP services locally in the mesh network when the Internet infrastructure is not accessible and operate through collaborative cooperation. In one embodiment, a Reported Node Time Server (RNTS) is elected when the mesh network is disconnected. In another embodiment, a Mesh Network Name Cache (MNNC) protocol pre-provisions each mesh node with the names and addresses of all other mesh nodes. In another embodiment, a Mesh Address Allocation Protocol (MAAP) provides DHCP services for DHCP clients in the mesh network.

Claims

1. A node in a wireless mesh network, comprising:

a memory configured to store code for a Mesh Address Allocation Protocol (MAAP) and code for a Mesh Network Name Cache (MNNC) protocol;

a display configured to display a user interface for interacting with at least one software application; and

a processor configured to operate the at least one software application, to operate the code for the MAAP and the code for the MNNC protocol, to access centralized Internet Protocol (IP) operational services in an Internet infrastructure, to dynamically switch to providing similar IP operational services to at least one other node in the wireless mesh network as soon as the wireless mesh network becomes disconnected from the Internet infrastructure, and to continue providing the similar IP operational services as long as the wireless mesh network remains disconnected from the Internet infrastructure.

2. The node according to claim 1 wherein the IP operational services provided by the processor comprise at least one of a Network Time Protocol (NTP) service and a Domain Name System (DNS) service.

3. The node according to claim 1 wherein the processor is further configured to automatically relay time or IP address information for the IP operational services to the other nodes in the mesh network that also dynamically switch to providing the IP operational services when the mesh network is disconnected from the Internet infrastructure.

4. The node according to claim 1 wherein the processor participates in an election process for operating as a master clock server for other nodes in the mesh network when the mesh network does not have access to a Network Time Protocol (NTP) server in the Internet infrastructure.

5. The node according to claim 4 wherein the election process dynamically selects one of the nodes in the mesh network as the master clock server according to how central the nodes are to the other nodes in the mesh network.

6. The node according to claim 4 wherein the election process dynamically selects one of the nodes in the mesh network as the master clock server according to clock times reported by the nodes or according to what alternative access the nodes have to other clock references.

7. The node according to claim 4 wherein the processor dynamically switches from using the elected master clock server in the mesh network to using the NTP server when the mesh network reconnects to the Internet infrastructure.

8. The node according to claim 1 wherein the processor is further configured to dynamically start operating the MAAP or the MNNC protocol whenever the wireless mesh network cannot communicate with an Internet DNS server or Internet DHCP sever, respectively, in the Internet infrastructure, wherein the processor is also configured to dynamically switch back to using the Internet DNS server or Internet DHCP server when the wireless mesh network reestablishes communication with the Internet infrastructure.

9. The node according to claim 8 wherein the processor is configured to receive a DNS or DHCP request from another node in the mesh network and reply with any DNS or DHCP information in a cache associated with the DNS or DHCP request, the processor further configured to forward the DNS or DHCP request to a next node in the mesh network when the cache does not contain information responsive to the DNS or DHCP request.

10. The node according to claim 9 wherein the processor is configured to assign a new IP address to a new node entering the mesh network, update the cache with a new DNS mapping including the new IP address, and then forward the cache updates to other nodes in the mesh network.

11. The node according to claim 10 wherein the processor drops a connection with the new node when the new IP address conflicts with an existing IP address assigned to another node causing the new node to reconnect to the mesh network for assignment of another new IP address.